Method of making glass fiber forming feeders and feeder formed thereby

ABSTRACT

A method of making an orificed discharge wall for supplying a plurality of streams of molten glass to be attenuated into filaments comprising inserting elements in apertures in a member; sealing said elements and member within a water soluble glass coating capable of isostatically transmitting pressure to said member and elements; hot isostatically pressing to the sealed elements and member to intimately bond the elements to the member; forming an orifice in said elements to permit the passage of molten glass therethrough to establish said streams.

TECHNICAL FIELD

The invention disclosed herein relates to the production of glass fibersand glass fiber forming feeders.

BACKGROUND ART

With the production of glass fiber forming feeders having anever-increasing number of orifices or tips to supply the streams ofmolten material to be attenuated into filaments, the need for effectiveand efficient systems for attaching the orificed tips or elements in theapertures in the discharge wall has also increased. Previously, theindividual projections or tips were welded to the discharge wall byconventional welding techniques, such as cold resistance welding,electron beam welding, and laser welding and the like. In essence, eachof these systems welded a single tip at a time. With fiber formingfeeders having as many as 4,000 or more tips, the welding process can bequite time consuming. Further, there are other problems associated withthe systems which are well known in the art.

DISCLOSURE OF THE INVENTION

This invention pertains to a method of making an orificed discharge wallfor supplying a plurality of streams of molten glass to be drawn intofilaments comprising: inserting elements in apertures in a member;hermetically sealing said elements and member within a water solubleglass coating capable of isostatically transmitting pressure to saidmember and elements; hot isostatically pressing the sealed elements andmember to intimately bond the elements to the member; and forming anorifice in said elements to permit the passage of molten glasstherethrough to establish said streams.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a semi-schematic front elevational view of a glass textiletype fiber forming system.

FIG. 2 is a semi-schematic front elevational view of a glass wool orrotary fiber forming system.

FIG. 3 is an enlarged cross-sectional view of the discharge wall of thefeeder shown in FIG. 1 during processing according to the principles ofthis invention.

BEST MODE OF CARRYING OUT THE INVENTION

As shown in FIG. 1, feeder 10, which is comprised of containment orsidewalls 12 and an orificed bottom or discharge wall 14, is adapted toprovide a plurality of streams of molten inorganic material, such asglass, through a plurality of orificed elements 85. Feeder 10, includingdischarge wall 14, is adapted to be electrically energized to heat theglass therein. The streams of molten glass can be attenuated intofilaments 16 through the action of winder 26 or any other suitablemeans.

As is known in the art, size applicator means 18 is adapted to provide acoating or sizing material to the surface of the glass filaments whichadvance to gathering shoe or means 20 to be collected as an advancingstrand or bundle 22. Strand 22 is then wound into package 24 upon acollet of winder 26 as is known in the art. Thus, FIG. 1 schematicallyrepresents a "textile" fiber forming system.

As shown in FIG. 2, rotary system 40 is comprised of a flow means orchannel 42 having a body of molten inorganic material 44, such as glass,therein. A stream of molten glass 46 is supplied to rotary feeder orrotor 50 from channel 42, as is known in the art.

Rotor 50, which is adapted to be rotated at high speeds, is comprised ofa quill 52 and a circumferential fiberizing or discharge wall 54 havinga plurality of orificed elements 85 adapted to supply a plurality ofstreams of molten inorganic material to be fiberized. Such elements maybe flush with the exterior surface of the wall or project outwardlytherefrom.

In conjunction with rotor 50, a shroud 56 and circumferential blower orfluidic attenuation means 57 are adapted to fluidically assist in theattenuation of the streams of molten material into fibers or filaments60. A binder material or coating may be applied to fiber 60 by means ofbinder applicators 58 as is known in the art.

As is shown in the drawings, member 69 of the fiberization or dischargewalls 14 or 54 of the feeders 10 and 50, respectively, may be based upona laminate comprised of a refractory metal core 70 having an oxygenimpervious, precious metal sheath intimately bonded thereto by hotisostatic pressing (i.e., HIP) as is disclosed in my patent applicationSer. No. 200,677, filed on Oct. 27, 1980, which is hereby incorporatedby reference. Or, member 69 may be comprised entirely of any suitablematerial, such as a platinum and rhodium alloy which, for example, iswell known in the art.

Regarding the laminated member, such refractory metals are selected fromthe group of materials consisting of molybdenum (Mo), columbium (Cb),tungsten (W), rhenium (Re), tantalum (Ta), hafnium (Hf), titanium (Ti),chromium (Cr), zirconium (Zr), vanadium (V), and base alloys of suchrefractory metals. For example, an alloy of molybdenum, titanium andzirconium, known as TZM, has been shown to provide a superior laminatedwall for a fiber forming feeder when clad with a precious metal alloy ofplatinum and rhodium.

Particularly, the precious metals for first layer 78, second layer 79and/or elements 85 are selected from a group consisting of platinum(Pt), paladium (Pd), irridium (Ir), osmium (Os), rhodium (Rh), ruthenium(Ru), and alloys based on such metals. Included in the platinum alloysare H alloy and J alloy which are alloys of platinum and rhodium of90%/10% and 75%/25% composition, respectively. In essence, the laminateis comprised of a plurality of layers of material wherein one of saidlayers is a refractory metal, and another of said layers is an oxygenimpervious, precious metal, said plurality of layers being intimatelybonded together by the simultaneous application of isostatic pressureand heat to form a unitary laminate.

FIG. 3 depicts a portion of a discharge wall at a point duringfabrication according to the principles of this invention. As such,elements or tips 85 are positioned or inserted in a plurality ofapertures 71 in member 69. As shown, element 85 is comprised of a sleeve87 having a flange 89 extending outwardly from first end 88 of sleeve87. Second end 91 of sleeve 87 is shown closed. However, it is to beunderstood that second end 91 may be open such that orifice 86 extendscompletely through sleeve 87. In any event, element 85 is finished suchthat orifice 86 provides a path for the molten glass to passtherethrough to establish the molten streams at the discharge wall 14.

The contacting portions of element 85 and member 69 should be in firmabutting engagement, including flange 89 if employed.

With elements 85 properly inserted in member 69, member 69 is positionedin or immersed in a bed or body of particles of water soluble glass 94.Conveniently, the bed of particles 94 is readily retained in container99. Container 99 may be formed of any suitable high temperatureresistant material capable of withstanding the temperatures employed inthe "fusing" step.

Container 99, containing powder 94 with member 69 having elements 85suitably positioned therein, is then heated to a temperature sufficientto melt or fuse the glass powder to hermetically seal the member andelements in a sheath of glass. Preferably, the heating or fusing step isdone under a vacuum, such as in a vacuum annealing furnace to alsoremove any residual gases that may reside between the member 69 andelements 85.

If the fusion step is performed in a separate oven or furnace, that is,other than the hot isostatic pressing chamber, the coated assemblyshould be permitted to cool below the solidification point of thecoating to permit handling of the coated assembly and to prevent thediffuse of air into or through the fused coating.

To provide a proper intimate or metallurgical bond between the elements85 and member 69, the coating material should satisfy three basicrequirements for use in a hot isostatic pressing chamber. First, thecoating material must be high temperature resistant. That is, thecoating must be able to withstand the temperatures employed in the hotisostatic pressing step. Second, the coating must form a gas tight orhermetical seal to prevent the working fluid in the HIP chamber fromentering between member 69 and elements 85 which may adversely affectthe bonding therebetween. And yet, thirdly, the coating must besufficiently pliable to be able to transmit the pressure applied theretoin the HIP chamber isostatically to the member and the elements. Yet thecoating must not be of too low a viscosity at the desired hippingtemperature, otherwise the coating may itself flow between member 69 andelements 85 or simply wash away therefrom.

Preferably, the glass particles 94 are comprised of a water solubleglass to permit the easy removal of the coating from the member 69subsequent to hot isostatic pressing by merely immersing the coatedmember in a body of water. The water may be heated to accelerate suchaction.

Suitable water soluble glasses, consisting essentially of SiO₂ and Na₂O, have been found to satisfy these requirements. Such sodium silicateglasses preferably contain from about 55% to about 80% SiO₂. Morepreferably, the SiO₂ comprises from about 60% to about 70% of saidglass. Tips have been bonded to orificed plates employing commerciallyavailable glass compositions of sodium silicate glass having a SiO₂component of about 66% of the glass.

With regard to viscosity of the coating material at the temperature atwhich the hot isostatic pressing step is carried out, the coating shouldhave a viscosity greater than about 500 poise at such temperatures.However, a coating exhibiting a viscosity at such temperatures is morepreferable within the range from about 500 poise to about 3,500 poise toprovide the proper pressure transmitting and sealing characteristics.

If the fused coating has cooled to below the solidification temperaturethereof, the coating is preferably heated to above the softening pointor temperature prior to any substantial application of pressure toprevent the fracture of the glass coating by the pressure. This mayconveniently be accomplished within the HIP chamber.

It is to also be understood that the fusion step may be carried outwithin the hot isostatic pressure chamber. This may be more readilyaccomplished in HIP chambers adapted to draw a sufficient vacuum duringheating to remove any residual gases from between member 69 and elements85. With the fusion step performed in a HIP chamber, the cooling cyclemay be dispensed with and the application of isostatic pressure mayproceed directly.

According to the foregoing procedures, if a tip 85, as shown in FIG. 3,is employed, the flange 89 will be intimately bonded to one surface ofmember 69, and sleeve 87 will be intimately bonded to the walls ofaperture 71 in member 69. Further, if a refractory metal/previous metallaminate and a precious metal insert 85 are employed, the sleeve 87 ofelement 85 will fuse to core 70 and layers 78 and 79 to seal therefractory metal within a protective layer of oxygen impervious,previous metal to prevent the oxidation of the refractory metal atelevated, or glass fiber forming, temperatures.

It is to be understood that element 85 may be of any suitable shape, forexample, flange 89 may be dispensed with and/or the length of sleeve 87may also be substantially equal to the thickness of member 69 to providea tipless orifice plate having orifices lined with a suitable materialintimately bonded to member 69.

An apertured platinum/rhodium plate or member was fitted with aplurality of platinum/rhodium tips or elements similiar to that shown inFIG. 3. The plate having the tips suitably pressed therein was placed ina molybdenum foil container and packed in a powder of water solubleglass particles (at a SiO₂ /Na₂ O ratio of 3.22:1). The packed containerwas then covered with a molybdenum foil lid to confine the glass powderduring the subsequent vacuum fusion treatment. The container was closed,but not sealed, to permit the withdrawal of the gases from the powderand between the elements and plate. The loaded container was then placedin a vacuum annealing furnace and the temperature was gradually raisedto about 900° C. while applying a hard vacuum. The furnace was held at900° C. under hard vacuum for about one hour to insure thatsubstantially all the trapped air between the tips and the plate wasremoved.

The container was then removed from the furnace after cooling to atemperature below the flow point of the glass (approximately 840° C.) toinsure that upon removal from the vacuum furnace, air will not diffuseinto the fused glass block or coating.

The container having the fused glass body containing the plate and tipswas positioned in the autoclave of a hot isostatic pressing unit andheated to the softening point of the glass (about 655° C.) at the lowestpermissible pressure for operation of the HIP unit. After reaching thesoftening temperature, the pressure within the HIP unit was graduallyincreased to about 15,000 PSI while gradually increasing the temperaturewithin the HIP unit to about 1,100° C. That pressure and temperaturewere maintained for about two hours to diffusion bond the tips to theplate.

After cooling, the foil container was removed and the glass bodycontaining the plate was placed in a water bath to dissolve the coatingto prepare the orificed plate for further fabrication into a completefiber forming feeder.

It is to be understood that the methods disclosed herein may be employedin preparing the laminated, orificed discharge wall for a glass fiberforming feeder set forth in U.S. Pat. No. 4,342,578 issued Aug. 3, 1982wherein the laminate is simultaneously bonded together as well asbonding the tips thereto.

From the foregoing, it can be seen that the present invention isapplicable to the joining of the precious metal elements to thelaminated walls or members as disclosed in, for example, U.S. Pat. No.4,342,577, issued Aug. 3, 1982, in the names of Mohinder S. Bhatti andAlfred Marzocchi; and/or U.S. Pat. No. 4,343,636, issued Aug. 10, 1982,in my name which are hereby incorporated by reference.

It is apparent that within the scope of the present invention,modifications and different arrangements can be made other than asherein disclosed. The present disclosure is merely illustrated, with theinvention comprehending all variations thereof.

INDUSTRIAL APPLICABILITY

The invention disclosed herein is readily applicable to the formation ofcontinuous and/or staple glass filaments.

I claim:
 1. A method of forming an orificed discharge wall for a feederfor supplying molten streams of glass to be attenuated into filamentscomprising:inserting elements in apertures in a member; immersing saidmember containing said elements in a bed of particles of water solubleglass; heating said bed of particles under a vacuum to fuse saidparticles to hermetically seal said member and elements in a hightemperature resistant and pressure transmittable coating of watersoluble glass and to remove residual gases from between said member andelements; hot isostatically pressing said hermetically sealed member andelements to intimately bond the elements to said member; contacting thecoating with water to remove said coating; and forming an orifice insaid elements to permit the passage of molten glass therethrough toestablish said streams.
 2. The method of claim 1 wherein said glassconsists essentially of SiO₂ and Na₂ O.
 3. The method of claim 2 whereinsaid SiO₂ comprises from about 55% to about 80% of said glass.
 4. Themethod of claim 3 wherein said SiO₂ comprises from about 60% to about70% of said glass.
 5. The method of claim 1 wherein said glass has aviscosity within the range from about 500 poise to about 3,500 poise atthe temperature at which said hot isostatic pressing step is carriedout.
 6. The dischare wall produced according to the method of claim 1.7. A method of making an orificed discharge wall for supplying aplurality of streams of molten inorganic material to be drawn intofilaments comprising:inserting elements in apertures in a member;contacting said member containing said elements with a layer of fusibleparticles; fusing said particles to seal said member and elements in acoating that remains highly viscous at elevated temperatures; coolingsaid fused coating to a temperature below the solidification temperatureof said coating; heating said member having the solidified coatingthereon to at least the softening temperature of said coating to rendersaid coating capable of isostatically transmitting pressure to saidmember and elements while retaining said member and elementshermetically sealed within said coating; and hot isostatically pressingsaid coated member and elements to metallurgically bond said elements tosaid member; and forming orifices in said elements to permit the passageof said molten material therethrough to establish said streams.
 8. Themethod of claim 7 wherein said fusing step is comprised of heating saidparticles under a vacuum to hermetically seal said member and elementsin said coating and to remove residual gases from between said memberand elements.
 9. The method of claim 8 wherein said fusible particlesare a water soluble glass.
 10. The method of claim 9 wherein said glassconsists essentially of SiO₂ and Na₂ O.
 11. The method of claim 10wherein said SiO₂ comprises from about 55% to about 80% of said glass.12. The method of claim 10 wherein said glass has a viscosity greaterthan about 500 poise.
 13. The method of claim 9 wherein said member is alaminate comprised of a plurality of layers of material wherein one ofsaid layers is a refractory metal and another of said layers is anoxygen impervious, precious metal, said plurality of layers beingintimately bonded together by hot isostatic pressing to form a unitarylaminate.
 14. The method of claim 10 wherein the refractory metal layeris a material selected from the group consisting of Ti, V, Cb, Ta, Cr,Mo, W, Re and base alloys thereof and wherein said precious metal layeris a material of the group consisting of Pt, Pd, Ir, Os, Rh, Ra and basealloys thereof.
 15. The method of claim 10 wherein said elements areselected from the group consisting of Pt, Pd, Ir, Os, Rh, Ru and basealloys thereof.
 16. A method of forming an orificed discharge wall forsupplying a pluralty of streams of molten glass to be drawn intofilaments comprising:inserting elements in apertures in a member;sealing said member containing said elements within a water solubleglass coating capable of isostatically transmitting pressure to saidmember and elements; hot isostatically pressing the sealed member andelements to intimately bond the elements to said member; and forming anorifice in said elements to permit the passage of molten glasstherethrough to establish said streams.
 17. The discharge wall producedaccording to the method of claim 16.